Somewhat timely. I just announced the death of my first SaaS project to the users (https://www.pingbrigade.com): a web site/server uptime monitoring system. What kept me going is that people kept signing up for the free accounts, but either the free offer was too good, or the paid offer didn't offer enough of an incentive to switch. Eventually, the minuscule costs of running the service started adding up to a number I could no longer ignore and I don't have time to do the marketing to acquire paid users. Logically it all makes sense, but it is hard to separate yourself from your failed project.